Continuous casting starter head



4 Sheets-Sheet 1 Filed Dec. 21, 1967 INVENTOR. William G. WilsonATTORNEY March 31, 1970 I w, w so 3,503,437

CONTINUOUSLCASTING STARTER HEAD Filed Dec. 21, 1967 4 Sheets-Sheet 2March 31, 1970 w. G. WILSON 3,503,437

CONTINUOUS CASTING STARTER HEAD Filed Dec. 21, 1967 4 Sheets-Sheet 3 on5 mm mm on mm mm on m .u\ i H Luv m \s m n} M w Q Q a 0L H. H H mm mo #01E March 31, 1970 w. w| so 3,503,437

CONTINUOUS CASTING STARTER HEAD Filed Dec. 21, 1967 4 Sheets-Sheet 4 a l"T 56 I" K W I Z 64 72 i 68 United States Patent 3,503,437 CONTINUOUSCASTING STARTER HEAD William G. Wilson, Beaver Falls, Pa., assiguor toThe Bahcock & Wilcox Company, New York, N.Y., a corporation of NewJersey Filed Dec. 21, 1967, Ser. No. 692,341 Int. Cl. B22d 11/08 US. Cl.164274 6 Claims ABSTRACT OF THE DISCLOSURE A starter head for continuouscasting having a recess in one end thereof and a tang extending from theopposite end of the starter head for attachment to a starter bar. Therecess having sockets in the opposite side walls thereof to receive abar forming a heat sink for attachment of initially frozen metal of thecontinuous casting thereto. At least one wall of the starter head recesscontaining a socket is transversely removable for insertion of the barand removal of the casting discard after use in the continuous castingoperation.

This invention relates to the continuous casting of metals, and moreparticularly to an improvement in the dummy or starter head and rodassembly used to initiate the casting of metals in an open endedcontinuous casting mold.

In the continuous casting of metals the mold is usually of the uprightfluid cooled type, open at both ends. In operation, molten metal isdelivered to the open upper end of the mold and an embryo casting isWithdrawn from the lower end of the mold. Since the mold is bottomless,it becomes necessary to insert a starter head or plug to temporarilyclose the bottom of the mold until the newly introduced molten metal hassolidified sufficiently to permit controlled withdrawal of the starterhead and the attached casting from the mold. After the continuouscasting procedure has been started, the starter rod and the head will beremoved for reuse in initiating a succeeding period of continuouscastmg.

Many different constructions have been utilized to provide a suitablehead and starter rod structure for initiating the casting process. Thetype of starter rod assembly is largely dependent upon the type ofcontinuous casting procedure utilized, i.e. Whether the starter rod mustfollow a curved configuration such as in the bow mold casting procedureor whether the continuous casting unit is arranged for verticaloperation. However, in all procedures the initially cast metal formingthe bottom of the continuous casting must be attached to the starterhead so that the starter rod will be effective in initiating thewithdrawal of the casting from the mold. This also necessitates theseparation of a minor portion of the initially cast metal with the headof the starter rod from the casting when the use of the starter assemblyis discontinued. Ordinarily the short length of metal casting attachedto the head will be discarded and at least some part of the dummy headas initially installed must also be discarded with the discard portionof the casting.

In the present invention I provide a starter head and a joined starterrod which may be readily disconnected in sections during the gradualWithdrawal of the starter rod from the mold. The starter head also mustbe detachable from the starter rod in such a manner as to permit removalof the starter head and the casting discarded from I the rod assembly.With the structure of the present invention the starter head is quicklyand easily parted from the discard portion of the casting and preparedfor subsequent successive use in initiating the continuous cast-3,503,437 Patented Mar. 31, 1970 ing process with a minimum of materialsdiscard. The starter head of the invention is particularly characterizedby the construction of its mating parts which are designed to hold scrapmetal pieces which later may be economically discarded along with thediscard portion of the casting. The starter head itself is easily andconveniently re assembled utilizing heat absorber materials which formthe key for connecting the head with the casting in each successive useof the apparatus.

Of the drawings:

FIG. 1 is an elevation of a continuous casting unit incorporating thepresent invention; 4

FIG. 2 is an enlarged section of the starter head or plug showing thedetails of construction of the detachable portions;

FIG. 3 is a section taken on line 3-3 of FIG. 2;

FIG. 4 is a longitudinal section view of the starter rod of the presentinvention;

FIG. 5 is a section taken on line 5-5 of FIG. 4;

FIG. 6 is an assembly, in section, of the dummy head installed at theend of the starter rod;

FIG. 7 is an enlarged section view of a detachable connector shown inFIGS. 4 and 5;

FIG. 8 is a section taken on line 88 of FIG. 7; and

FIG. 9 is a section taken on line 9-9 of FIG. 8.

As shown in FIG. 1 the continuous casting unit is of the vertical typeand includes a molten metal pouring apparatus such as a ladle 10 andtundish 11 for the delivery of molten metal to the continuous castingmold 12. The molten metal is solidified, at least in part, within themold 12 and is passed downwardly therefrom to an aftercooling section13. Leaving the section 13 the casting is passed through a set ofwithdrawal rolls 14 which regulate the rate of movement of the casting15 from the mold. The casting is solidified before or shortly afterpassing through the withdrawal rolls 14, and in leaving the rolls 14will be cut to length for ease of handling by an oxygen lance 16 or thelike. As shown in FIG. 1 the cut lengths of castings or ingots 17 willbe removed by a handling mechanism 18 which lowers the ingot to aconveyor 20, for delivery to a place of storage or for furtherprocessing.

As shown, the ladle 10 is of the bottom pour type and is supplied withmolten metal from one or more furnaces (not shown), transported to apouring location by an overhead crane (not shown) or other similardevice, and mounted for effective positioning relative to the tundish11. When the ladle is properly positioned, molten metal is dischargedtherefrom through a nozzle at a controlled rate for delivery of themolten metal to the tundish. The tundish is usually constructed andarranged for bottom pouring and provides for a maximum elimination ofslag before the molten metal is delivered to the casting mold 12.

The embryo casting 15 leaving the lower end of the mold '12 will have afrozen metal skin of sufiicient thickness to confine the molten metalcore therein as it leaves the discharge end of the mold. The castingthen passes through the after-cooling section 13 where it is furthercooled by streams of water directed against its Walls. Additionally thecasting is supported by a mechanism intended to inhibit swelling of thecasting during the cooling process. Such an after-cooling and supportsection for continuous casting is shown, for example, in U.S. Patent2,770,021.

In the embodiment shown, the casting 15 leaving the withdrawal rolls 14is cut to preferred lengths by means of an oxygen torch 16. Since thecasting is moving downwardly during the casting operation it isnecessary for the torch to move with the casting while cutting to thedesired length. The ingot 17 cut to desired length is engaged by ahandling mechanism 18 which is arranged to transport the ingot 17 froman initial vertical receiving position to a horizontal dischargingposition. The ingot 17 is then removed from the casting unit by theroller con- 'veyor:20.

Prior to initiating the continuous casting operation it is necessary toposition a dummy or starter head 25 in the bottom of the mold 12 (seeFIGS. 2 and 3). The head 25 is supported upon a sectional starter rod 26which extends upwardly from the pinch rolls 14 to a preferred positionof the head within the lower portion of the mold 12. When the castingoperation is starting the molten metal poured into the mold freezesabout the keying structure of the starter head 25 thereby forming aneffective stopper or plug. When the proper molten metal level in thecontinuous casting mold 12 has been attained, Withdrawal of the starterrod 26 with the initially frozen casting metal secured to the head maybe initiated. As each jointed section of the starter rod 26 (ashereinafter described) leaves the withdrawal rolls 14, such section canbe removed until the head 25 itself passes through the rolls. The torch16 will then be actuated to cut the pendant casting at a positionupwardly adjacent the head 25 so that the head and the frozen metaldiscard attached thereto may be removed from the last section of thestarter rod. Thereafter the continuous casting operation continues in anormal manner until all of the molten metal has been processed.

If the continuous casting unit is being operated with closely spacedindividual pours the dummy head 25 may be disengaged from the discardmetal of the casting while the normal continuous casting procedure isbeing followed. With the removal of the discard and the expendableportions of the dummy head, the dummy head may then be re-assembled ashereinafter described to be ready to initiate the next succeeding moltenmetal pour.

In the illustrated embodiment of the invention shown in FIGS. 2 and 3the starter head 25 is shown as constructed and arranged for use in acontinuous casting mold '12 of rectangular horizontal cross-section. Inthe specific example the mold cross-section is approximately by 8%". Insuch a mold the starter head 25 is constructed to loosely fit in thelower portion of the mold 12 when installed for initial operation of thecontinuous casting unit. Before molten metal is supplied to thecontinuous casting mold '12 the clearance space between the periphery ofthe head and the mold wall may be packed with asbestos rope or othersealing material.

The head 25 is formed with a recess 32 in the upper surface thereof toreceive the molten metal initially supplied to the mold. As hereinafterdescribed in greater detail, the recess is provided with disposablemetallic bars supported in opposing walls of the recess to key into andbecome an integral part of the lower end of the casting when the moltenmetal solidifies.

As shown in FIGS. 2 and 3, the upper end portion of the head 25 isconstructed in two parts. One of the parts 27 is formed to provide wallsfor generally one-half of the molten metal receiving recess 32 and isfurther provided with a lower extension which forms the tang 28 forattachment to the starter rod 26 as by a bolt 39. The mating part 31 ofthe head 25 is constructed as a transversely removable portion of theupper end of the head forming the walls of the remaining portion of therecess 32. The part 31 has a fiat bottom 34 slidably supported on a base35 constructed as a projecting shoulder of the part 27. To insure aproper connection with the matching surf-aces of parts 27 and 31, atongue 33 of part 31 projects into a groove 36 correspondingly formed inthe part 27. When assembled, the parts 27 and 31 form a head 25symmetrical about a longitudinal axis and having the centrally disposedrecess 32 open at the top to receive molten metal. As shown in FIGS. 2and 3, the recess is generally rectangular in cross-section and isbounded by generally upright side wall surfaces 30. The wall surfaces 30may be slightly inclined inwardly or outwardly without seriouslyaffecting the casting keying function of the head 25. The parting lineof the mating portions of the dummy head is indicated by the numeral 37.When assembled, the two portions are held together by a pair ofhorizontally spaced threaded bolts 38. Opposite walls of the head 25 areprovided with sockets 40 and 41 to accommodate loosely fitted bars 42which are inserted before assembly of the two parts of the head. Thuswhen the two parts are bolted together the bars have their opposite endsengaged in the sockets to form a keying arrangement and heat sink aboutwhich molten metal freezes to permit withdrawal of the embryo castingfrom the continuous casting mold. In addition to the bars positioned inthe recess 32 of the head, other metallic bars 43 are positionedtransversely across and resting on the upper surface of the bars 42 toprovide metal for an additional heat sink and to aid in providing theattachment between the initially formed frozen metal of the continuouscasting and the head. As a further protection to the head assembly aflat plate 44 is inserted in the bottom of the recess 32, resting on theupper surface of the mating portions of the dummy head. Thus when moltenmetal is delivered to the mold 12 initial freezing of the molten metalwill occur around the bars 42 and 43 but not between the mating portionsof the head. The cover plate 44 will also serve as protection for thebottom surface of the recess 32.

With the molten metal freezing about the bars 42 and 43 the casting asit freezes may be withdrawn from the mold at a controlled rate byoperation of the withdrawal rolls 14. When the head 25 with the newlycast metal has been withdrawn below the rolls 14 the initially frozenportion may be cut from the casting and the head 25 with the end portionof the starter rod may be removed from the casting apparatus. The headmay then be disconnected from the starter rod 26 by removal of the bolt39. With the head 25 and the frozen metal discard end of the continuouscasting forming a single unit the head may be separated along itsparting line 37 for removal of the casting discard along with theexpendable parts 42, 43 and 44. It will be understood that these partswill have generally lost their separate identity in fusing into thecasting discard. The head parts 27 and 31 may be separated by hydraulicor mechanical apparatus provided with pairs of prongs which engagesockets 45 and 46 formed in the respective parts 27 and 31 for thisspecific purpose.

The starter rod 26 shown in FIGS. 4 and 5 includes a series of connectedrod-like segments or sections 50 which are arranged for successivedisassembly and removal when each section is drawn below the withdrawalrolls 14 shown in FIG. 1. As shown specifically in FIGS. 4 and 5 theupper end of the starter rod, to the left in the figures, includes atapered segment 51 which is attached by bolt 39 to the upper end of thestarter rod 26. When preparing a continuous casting unit for castingservice, the assembled rod is threaded up through the rolls 14 with theupper end segment 51 extended through the mold 12. The tapered segmentis then removed from the starter rod 26 and the head 25 installed in itsplace, as is shown in FIG. 6. With the head 25 attached by the bolt 39the assembly is lowered until the head is positioned with respect to themold 12 as shown in FIGS. 2 and 3.

The starter rod assembly is made up of a series of sections 50 which maybe of any selected length with each of the sections connected by meansof a quickly detachable connector element 55, hereinafter described, toan adjacent section. The connecting elements 55 between adjacentsections are shown in detail in FIGS. 7, 8 and 9.

The sections 50 each include a spacer element 54 fabricated of steelplates formed in the general configuration of the cavity of the mold 12,and which is suitably reinforced to withstand the operating load on theassembled sections. The spacer elements 54 may be of any desirablelength so that the assembled starter rod 26, including the spacerelements 54 and the connecting elements 55, may form a unit of thedesired length. It is, of course, understood that the length of thestarter assembly must be sufficiently long to extend from the mold 12through the withdrawal rolls 14 so that as the continuous castingprocess is begun, the initially frozen continuous casting which is keyedinto the starter head 25, and the starter rod 26 may be graduallyWithdrawn thereby initiating the continuous casting operation.

Referring to FIGS. 7, 8 and 9 it will be noted that each of theconnection elements is formed as a two-part structure which is heldtogether by means of a rotatable shaft or rod 56 to provide a bayonettype joint. The opposite ends of the elements 55 are each provided witha tang 57 and 58 which extends outwardly from the end plates 60 and 61respectively, with such tangs having transverse openings 62 and 62'respectively and connected by means of pins or bolts 63, to thecorresponding end portions of the spacer elements 54.

As illustrated, the mating portions of the connecting element areconstructed of welded plates formed to include open ended recesses whichaccommodate the elements of the bayonet type joint. As shown in FIG. 7,the lower portion A of the element is provided with a block 64 whichfits into the lower recess 65 and is provided with springs 66 interposedbetween the block 64 and the end plate 60. The block 64 is provided witha transversely arranged machined opening 67 in register with matingholes drilled in the side walls of the lower portion A to receive asleeve or bushing and pin 68. When the pin is installed, the block 64 isrigidly connected within the lower portion A of the connecting element.

An upwardly extending cap element 70 projects into a recess 74 formed inthe upper portion B of the element 55 and is provided with a downwardlyextending stud 72 which is threaded into a corresponding aperture 73 inthe block 64. The cap element 70 has a transversely extending machinedslot 75 of circular cross section having an open upper face 76. Therotatable shaft or rod 56 is journaled in the side walls of the upperportion B of the connecting element and projects through the slot 75 ofthe cap 70. The pin 56 is provided with parallel flattened faces 77 sothat when it is rotated 90 from the position shown in FIG. 7 the lowerportion A of the connecting element together with the block 64 and capelement 70 may be withdrawn from the upper portion B.

While the connector element 55 must provide a strong, stable connectionbetween the sections of the starter rod, the bayonet type joint mustalso be constructed with sufficient flexibility to permit assembly anddisassembly during all reasonable conditions of operation. The gap atjunction line 80 and the springs 66 will give ample correction formisalignment of the dummy sections when connecting. Shim plate 81 shouldbe accurately sized so that when cap element 70 is screwed into block64, the centerline of the machined slot 75 is 90 to the centerline ofpin 68, and the shim plate 81 is held tightly between cap element 70 andblock 64. The base of the cap 70 is provided with a locking finger 82attached to a side of the block 64 to lock the parts in the preferredrelationship.

The shaft 56 is provided with an indentation or socket 83 at oppositeends into which a turning tool, such as a socket wrench, may be insertedfor engaging and disengaging the bayonet type joint. The shaft 56 iscompletely enclosed within the bore 75 by end plates 84 having enlargedcentral openings 85 see FIG. 9 therethrough in alignment with eachsocket 833. The opposite peripheral end portions of the shaft areincreased in diameter to accommodate thrust springs 86 which bear on theend plates 84 and tend to center the shaft 56 so that the flats 77thereon are 90 from alignment with the open slot 76 in the upper face ofcap 70 when the wrench is removed and no torque is applied to shaft 56.

The construction described permits effective use of the starter rod 26under all conditions of operation, and facilitates ready use of thebayonet type joints between sections for assembly and disassembly of thestarter rod.

What is claimed is:

1. Apparatus for continuous casting comprising a continuous castingmold, means for delivering molten metal to said mold, an elongatedstarter bar, a head section detachably connected with an end of saidstarter bar, said head section having an exterior configurationsubstantially conforming with the interior of said casing molding andinsertable therein and having a plurality of separable portions, saidstarter bar head section being characterized by walls defining a recessin the upper end thereof to receive the initial molten metal deliveredto said mold, a metallic bar positioned intermediate the depth of saidrecess and extending transversely across said recess, said bar beinggenerally normal to the axis of said starter rod, and means fortransversely detaching at least a portion of said head section includinga wall portion of said recess supporting one end of said bar from theremaining portion of said head whereby the metallic bar and the castmetal solidified therearound can be detached from said head.

2. Apparatus for continuous casting according to claim 1 wherein thewalls defining said recess are provided with sockets formed in oppositesides thereof to loosely accommodate said bar.

3. Apparatus for continuous casting according to claim 1 wherein a metalplate is positioned across the bottom of said recess to protect saidhead from molten metal depositing thereon.

4. Apparatus for continuous casting according to claim 2 wherein thetransversely detachable portion of said head includes approximatelyone-half the exposed portion of said recess.

5. Apparatus for continuous casting according to claim 1 wherein aplurality of metal bars are transversely spaced across said recess, andother metallic elements are laid on said bars to form a heat sink forsolidifying the molten metal delivered thereto.

6. A starter head for continuous casting comprising a head portionhaving a central recess in one surface and a tang extending from theopposite end thereof, means forming countersunk sockets paired inopposite side walls of said recess and spaced intermediate the open topand closed bottom of the recess, a bar extending across said recessbetween said sockets, said head having an upper portion having aplurality of separable elements and bottom portion transverselyremovably connected thereto, said upper portion and bottom portionincluding at least one wall of said recess containing one of an oppositepair of said sockets.

References Cited UNITED STATES PATENTS 3,266,104 8/1966 Foldessy et a1164-274 3,333,627 8/1967 Forster l64282 3,448,789 6/1969 Gallucci164-274 FOREIGN PATENTS 929,478 6/1963 Great Britain.

I. SPENCER OVERHOLSER, Primary Examiner R. S. ANNEAR, Assistant Examiner

